The present invention relates generally to wireless communication networks, and more particularly, to a monitor and control system for satellite communication networks and the like.
Conventional satellite communication networks have found widespread use by television networks, telephone companies and the like. In recent years, with the advent of digital communications, communications via satellite links have become more readily available to small businesses and individuals. Of particular interest is the satellite linkage between remote computers and global computer network systems, such as the Internet.
Digital satellite communication systems typically include a hub terminal for communicating with multiple remote terminals, which typically include computers or other digital data-processing devices. One or more modems are connected to each hub terminal for modulating and demodulating data to be transmitted on the satellite""s frequency band. To accommodate more than one remote terminal at a time, the hub terminal communicates with each remote terminal on a different frequency or channel of the satellite""s transponder spectrum. This arrangement is known as a star network. In another method known as time-division multiplexing, many different remote terminals use the same frequency, but transmit data in packets arranged in selected time slices of the data stream.
To effect multiple communications, the hub terminal transmits various control signals for commanding the remote modem, such as signals for tuning to a particular channel for data transfer. The hub terminal receives various signals from remote terminals for monitoring the network operation. Monitoring signals also permit the hub terminal to monitor usage of the remote terminals. This feature has found particular application for billing remote terminal users for satellite time. The control and monitor signals are transmitted on the same frequencies using the same equipment or different frequencies using different equipment.
In effect, a network is provided where one remote terminal communicates with another without using the hub terminal. This is known as a xe2x80x9cmeshxe2x80x9d network, i.e., any terminal within the network may communicate directly with any other terminal. Two transmission frequencies are allocated to each pair of terminals for two-way communication. The main advantage of mesh networks over star networks is that mesh networks are more frequency efficient. That is, in a mesh network a communications link between two points requires the use of two transmission frequencies, whereas in a star network, all data must pass through the hub so that four transmission frequencies must be used.
In a mesh network the main task of the hub terminal is to allocate frequencies to the terminals and to continue to monitor the mesh network. The control and monitoring task in a mesh network is more complex than it is in a star configuration. One solution that has been proposed to carry out the control and monitoring tasks in a network mesh is the use of a special frequency with a dedicated modem at each terminal. This approach, however, requires the use of additional hardware at the remote site, thereby adding to the cost and complexity of the system.
The use of dedicated equipment in the remote terminals to perform the control and monitoring task is possible during the initialization phase, that is, before the terminal is communicating with another terminal. However, after a link is established between two terminals, the control and monitoring of those terminals by the hub with such dedicated terminal equipment would require the interruption of the data traffic stream. There is thus a need for a satellite communication monitor and control system in which dedicated terminal traffic equipment can be used to monitor and control data communication without interfering with the data traffic stream.
It is an object of the present invention to provide an economical and efficient monitor and control system for satellite communications networks and the like.
It is another object of the present invention to provide an improved monitor and control system for satellite communications networks that is reliable and utilizes a hub station for monitoring and controlling links between remote terminals.
A further object of the present invention is to provide a non-intrusive monitor and control system which facilitates ready transmission of a data stream between remote terminals of a mesh network.
Yet another object of the present invention is to provide a fully functional monitor and control system for satellite communications networks without sacrificing efficiency.
Still another object of the present invention is to provide a monitor and control system of the type described that yields optional bandwidth on demand features to remote terminals.
Yet a further object of the present invention is to provide a monitor and control system for a satellite communication network that permits a service provider to charge for actual satellite usage while providing broad bandwidth on demand.
According to one aspect of the present invention, a monitor and control system for satellite communication network includes a hub computer terminal arranged in a network with a plurality of remote computer terminals to form a mesh communications network. The hub terminal has frequency and time division multiplexing functions for transmitting and receiving monitor and control data packets to and from respectively each remote terminal, and for utilizing frequencies already in use by the remote terminals without interfering with passage of data between remote terminals.
Also described is a method of monitoring and controlling the passage of data through a satellite communication network in which a hub computer terminal is arranged in a mesh communications network with a plurality of remote computer terminals. Monitor and control data packets are transmitted to and received from each remote terminal via frequency and time division multiplexing functions of the hub terminal, so as to utilize frequencies already in use by the remote terminals without interfering with passage of data between remote terminals.
The present invention will now be further described by reference to the following drawings which are not intended to limit the accompanying claims.